CSC 4402 20090831 - Relational data manipulation is...

CSC 4402 8/31/2009 Page 1 of 1 Data models A data model is a collection of tools for describing: • Data • Data relationships • Data semantics • Data constraints The 3 major components of any data model are: • Data structures • Data manipulation • Data integrity An object-oriented/object-relational database starts with a relational database, but is expanded to support operations that maintain the relationship between objects and data. Relational data model The relational data model is based on a data structure of tables.

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Unformatted text preview: Relational data manipulation is performed by relational algebra or relational calculus. There are two integrity rules: 1. Entity integrity – you cannot have invalid values in an entity 2. Referential integrity – When referencing values from one table to another, the referenced value is guaranteed to exist. Database languages Structured Query Language (SQL) is a declarative DML. SQL contains a DDL and DML. Database design...
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